Experts warn: brown rot in potatoes is a threat to the crop.

Experts from the Altai branch of the Federal State Budgetary Institution "Grain Quality Assessment Center" explain that the first sign of brown rot infection is the appearance of copper spots at the base of the leaves. Then the leaves begin to curl and wilt in just one day.

"In favorable weather conditions, the disease can develop so rapidly that already practically dead stems and curled leaves remain green. Brown rot is also called 'slimy disease.' This name the disease received due to the fact that tubers of affected plants usually decrease in size and completely rot, as if covered with gray slime. At the same time, they emit a sharp unpleasant smell," say specialists from the Altai branch of the Federal State Budgetary Institution "Grain Quality Assessment Center."

Inside the tubers, rings of brown color form, from which a fluid resembling pus is secreted. The eyes of the potato and the point of attachment of the tuber to the stolon are also covered with rotting slime, and lumps of soil begin to accumulate on the tubers. Rot can develop both in the field and during storage after harvesting.

Brown rot spreads through infected soil, where pathogenic bacteria can remain active for up to three years. In addition, tubers and plant residues can also serve as sources of transmission of this disease. Bacteria can enter plants through stem damage caused by both mechanical injuries and insect activity.

Chemical means of protection against this disease usually do not have high efficiency. Therefore, the main measures to prevent the spread are planting resistant potato varieties, actively destroying weeds and plant residues in the fields.

Farmers are also advised to regularly disinfect agricultural equipment and monitor the conditions of storage of seed and table potatoes.

"In the Altai branch of the Federal State Budgetary Institution 'Grain Quality Assessment Center,' research for the presence of brown rot in potatoes is carried out using the PCR method, which includes three stages. First, plant material preparation is carried out – extraction of DNA or RNA using special reagents. The second stage is amplification, that is, the strengthening of the DNA thread. This is done to determine if the DNA thread belongs to the specific pathogen. At the final stage, the amplified DNA is detected, which involves identifying the obtained result," say specialists from the Altai branch of the Federal State Budgetary Institution "Grain Quality Assessment Center."

Usually, potato samples intended for consumption come to the testing laboratories in the form of tubers. This is due to the risk of disease spread through seed material to other regions and countries.

Experts in the laboratories conduct research on potatoes to meet the requirements of the Eurasian Economic Union Council Decision of 30.11.2016 No. 157 "On the Approval of the Unified Quarantine Phytosanitary Requirements for Subquarantine Products and Subquarantine Objects at the Customs Border and on the Customs Territory of the Eurasian Economic Union." These requirements include checking potatoes for the presence of brown rot.

Specialists note that it is impossible to visually determine the presence of the disease at an early stage. Rot begins even without soil if diseased potatoes are left for some time. The bacterium becomes visible only after the final spoilage of the product. Therefore, laboratory research plays a key role in combating the spread of brown rot and ensuring the preservation of the potato crop, allowing for the precise identification of the disease agents in commercial and seed material.